Shaft truing device



May Z1, 1940. .1. P. FERGUSON y 2,201,664

'SHAFT TRUING DEVI CE Filed April 26, 1937 2 Sheets-Sheet l ATTORNEYS.

May 21, 1940. J. P. FERGUSON SHAFT TRUING DEVICE Filed April 26, 1937 2 Sheets-Sheet 2 INVENTOR. 'rd/M755 P @Wr/50N.

BY my ximg-fw@ ATTORNEYS.

Patented May Z1, 1940 UNITED STATES PATENT OFFICE 6 Claims.

This invention relates to shaft truing devices, and particularly to a device for truing automobile crank shafts and other shafts which have portions thereof which have been worn to eccentric cross sectional shape.

The primary object of the invention is to provide a simple device by which a shaft may be rapidly and accurately reshaped in true centered form.

A further object is to provide a device of this character with means for accurately guiding the shaft shaping element.

A further object is to provide a device of this character adapted to operate upon a stationary shaft.

A further object is to provide a device of this character with novel means for'driving the shaping element. i

A further object is to provide a device of this character with means for resisting torque applied by the drive means of the device.

A further object is to provide a device of this character which can be readily applied to and removed from the work.

A further object is to provide a device of this character adapted to automatically apply increased pressure on the shaping element at the high spots on the Work.

A further object is to provide a device of this character which is adaptable to a wide range of shaft sizes, and is at the same time highly accurate.

A further object is to provide a device of this character with a novel shaping element.

Other objects will be apparent from the description and the appended claims.

In the drawings:

Fig. 1 is a face view of the device, with parts broken away.

Fig. 2 is a sectional view taken on line 2-2 of Fig. 1.

Fig. 3 is a view on a reduced scale illustrating the application of the device in use.

Fig. 4 is a fragmentary sectional View illustrating the application of the device on a crank shaft.

Fig. 5 is a longitudinal sectional view of an abrasive type of shaping element.

Fig. 6 is a fragmentary transverse sectional View of the shaping element.

Fig. 7 is a fragmentary transverse sectional View of theshaping element and its mounting.

Fig. 8 is a fragmentary detail view of a sectional gear.

Fig. 9 is a face view of a modied construction of the shaping element, with parts shown in section.

Fig. 10 is a fragmentary longitudinalY sectional view taken on line lll- I0 ofy Fig. 9.

Fig. l1 is a fragmentary longitudinal sectionalview taken on line l I-Iil of Fig. 9.

Fig. 12 is a fragmentary face view illustrating a detail of the cutting element drive.

Referring to the drawings, and particularly to Figs. 1 to 8, wherein I have illustrated one embodiment of my invention, which utilizes an abrasive type of shaping element; the numeral 20 designates a frame comprising two parts tting tightly together at a parting plane 2l. Frame 2S is provided with a circular passage 22 therethrough whose axis lies in the parting plane 2l. An annular groove 23y is formed centrallyl between the face of frame 20 in communication with passage 22. Suitable means are provided for locking the frame parts in registry, said means preferably comprising bifurcated brackets 24 mounted on opposite edges of one frame part adjacent the parting face thereof, and brackets 25 mounted on the coresponding edges of the other frame part. To the brackets 25 are pivoted at 26 the link members 21 which are screw. threaded at their free ends and adapted to be received by the adjacent bracket 24 against which screw threaded caps on said links may bear to draw the frame parts tightly together. Index pins 29 project from the parting face of one frame part and t into recesses in the parting face of the other frame part to guide the parts into accurate registry upon tightening of caps 28.

One of the frame parts 20 is provided with a thickened portion 30` extending parallel to and opposite its parting face, said portion 30 being chambered to receive a worm gear 3| mounted on a shaft 32 journaled in bearings 33 and having one end projecting from said frame and terminating in a squared or configured end portion 34. The chamber of portion 30 communicates with groove 23 by virtue of the partial intersection thereof. A bracket 35 is mounted on the edge of portion 30 and mounts a projecting pin 36 for purposes to be hereinafter set forth. y

Within the passage 22 of frame 20 isvmounted a two-part ring 40 provided with an integral gear 4I on its outer periphery, said gear being of reduced width to fit in groove 23. The gear ring 40 is accurately machined to size whereby its outer periphery fits snugly in frame passage 22 without binding and without play when its parting faces abut. The gear ring parts are preferably unconnected and are held to place solely by their iit in frame 20. However, a mechanical connection between the gear parts may be ernployed if desired as illustrated in Fig. 8, wherein links 42 are secured to the ends of the ring portions, the said links preferably seating in suitable recesses provided therefor in the face of the ring parts.

A two-part adapter ring 45 fits snugly in the gear ring 4D. This adapter ring is provided with integral projections 46 at its outer periphery which fit in conplementary recesses in the gear ring and thereby lock the adapter ring to the gear ring in driving relation. To the inner periphery of the adapter ring 45 is applied a ring 41 of rubber or other suitable resilient material, said rubber being bonded to the adapter ring in any suitable manner. To the inner periphery of the rubber ring 41 are bonded a plurality of thin arcuate metal plates or segments 48. In predetermined spaced relation about the circumference of ring 41 are provided parallel apertures, and the adjacent ends of said segments 48 are slightly spaced in communication with said apertures. A strip 49 of suitable flexible material provided with an abrasive facing fits within the circular opening defined by segments 48. Strip 49 is passed between the spaced segments and into the apertures in ring 41 to be secured to place by pins 5D mounted in said apertures and encircled by said strip. Abrasive strip 49 is preferably of narrower width than segments 48, and the latter may be recessed to partially receive said strip and provide shoulders 5| at its sides, as illustrated in Fig. 5. An alternative construction is illustrated in Fig. 4, wherein strips 52 of felt are mounted on the segments at the sides of edges thereof not covered by abrasive 49.

The manner in which the device is used is best illustrated in Fig. 3, wherein a fragment of an automobile engine is illustrated in section, including crank shaft 55 and lower motor housing 56 from which the usual oil pan has been removed to provide an opening for access to the shaft. The shaft 55 is measured to determine the extent to which the same must be reworked to be trued and at the same time permit fitting of a standard undersize journal thereon, and an adapter ring assembly is then selected according to these requirements. This assembly includes the adapter ring 45, rubber ring 41 and segmental inner facing 48; which assembly is, of course, in two semi-circular parts. The desired abrasive strip 49 is then applied to this assembly. The adapter assembly is then applied to and mounted in the gear ring, and the whole is applied around shaft 55. Frame parts 20 are then applied and secured around the gear ring in operative relation by means of links 21 and associated parts. vAn angle member 51 may then be secured to housing 56 at the opening thereof and adjusted to bear against torque pin 36 and oppose the torque applied to frame 20 by operation of the device. A suitable power driven unit 58 having a socket 59 for connection with the squared end 34 of shaft 32 completes the assembly.

Upon operation of power unit 58, the shaft 32 and worm gear 3| are rotated to drive the gear ring 40 meshing with said worm gear. The ring gear 40 in turn rotates the adapter ring assembly with its abrasive inner face, the drive being effected by the pins 46 between the gear ring and adapter ring. In all shafts upon which parts are journaled, such as crank shafts, the portion which must be trued is limited, and the part of the shaft extending beyond the ends of the journal remains true. This part has here been designated 60, see Fig. 4, and provides means for facilitating the operation of the instant device. The abrasive strip 4S is of a width just sufficient to act upon the defective portion of the shaft, whereby the portions of the adapter unit projecting beyond the strip may form guides which bear upon the portions 60 as tracks to guide or control the truing operation. In other words, the shoulders 5| of the construction shown in Fig. 5, or the felt strips 52 of the construction shown in Fig. 4, serve as guides cooperating with the track or pattern portion 6D of the shaft. It will thus be seen that, as the device operates, the guides bear on the shaft portions 60 adjacent the low spots on the shaft to limit the depth of the cut taken by the abrasive at such points. However, at the high spots on the shaft, the rubber backing ring 41 is compressed, causing greater pressure on the abrasive at such points until such time as such high spots have been eliminated, when the guides engage with the shaft portions 60 to limit and stop the action of the abrasive. In this way it is obvious that the device automatically centers the shaft area worked, and positively trues the same. The aforementioned operation of the device involves,

of course, greater compression of rubber ring 41 at the high spots than at the low spots of the shaft. This factor, coupled with the fact that the rubber ring rotates, also involves continued or progressive moving of the point ol compression of the ring. To accommodate these conditions, the segmental plates 48 are provided, it being obvious that the same provide the necessary substantially rigid backing for the abrasive strip and at the same time permit limitation of the compression of the rubber backing at any one portion thereof to the immediate vicinity of the "high spot. In other words, the segments 48, being independent, may give individually when the portion of the rubber ring to which each is bonded passes into the restricted zone of the high spotf to permit the momentary increase of pressure on the rubber and abrasive at that portion of the shaft only. It will thus be seen that the instant device serves not only to restore the shaft to true circular form with respect to its normal or proper axis, but also to limit its truing action positively to cuttirig down of the high spots as distinguished from an action of turning the shaft to circular form centered between the high spots and low spots on the shaft as worn at the time the operation is begun.

It will be obvious that the instant device requires a very accurate relation between the guide surface and the abrasive surface to limit the depth of the cut, with consequent care in selection of the abrasive strip as regards its thickness; and likewise, each of the adapter units must be accurately manufactured as respects its inner peripheral dimension. The accuracy of the work accomplished by the device is directly determined by the above factors, and when they are accurate, the device will automatically impart the same accuracy.

Inasmuch as the interposition of the rubber ring 41 between the metal abrasive backing segments 48 and the metal adapter ring 45 is necessary to the operation of the device, and that rubber ring must take the circumferential stress incident to transmitting the driving force from the adapter ring to the abrasive unlesssome mechanical interconnection of the parts is provided, it may be desirable to provide such interconnection. This can be accomplished without interfering with the resiliency of the rubber over the high spots by the construction shown in Fig. '1. In. that construction, tapped radially extending holes are formed in the adapter ring 45 for the reception of a bolt 6|; and a slightly larger concentric hole is formed in the rubber ring 41 and adjacent segment 48 for the reception of the bolt head 62. Bolt head 52 is of a length to extend from the inner periphery of the adapter ring to approximately the mid-point of the segment 43 with respect to the thickness of the latter. Thus, as rotative stress is applied to the adapter ring by the gear ring, the same is directly and m-echanicallj7 transmitted to 'the segments 48 by the `bolt heads 62 without circumferentially stressing or deforming theintervening rubber. If desired, the bolt may also extend into a threaded aperture in gear ring 48 and thereby serve additionally to securevthe adapter ring to the gear ring whereby the number of parts required to be handled in assembling and disassembling the device is minimized. f A modified construction of the device operating as a cutter is illustrated in Figs. 9 to 12. In this construction a two-part gear ring 10 adapted to t in frame 28 in the same manner heretofore described is employed. It is desirable that the ring parts be mechanically interlocked in this construction, for which purpose bolts 1| are ernployed. The radial dimension of the ring between its inner and outer peripheries is substantially greater than in the previously described embodiment.

In one part of ring 18 a pair of configured guideways 12 extending parallel to the ring axis and opening at the inner periphery of the ring are provided, said guideways being spaced approximately 120 degrees. Each guideway mounts a pair of configured bearings 13. The bearings 13 each include a substantially rectangular body portion 14 of a width'approximately one-half the width of ring 18. Radially inwardly from the body portion 14 projects an integral tapered portion 15 of reduced size, the outer end of the inner edge of which tapered portion projects at 1t for purposes to be hereinafter set forth. Radially outwardly from body portion 14 projects a reduced dimension portion 11 of less width than the body portion as best shown in Fig. l0. At the sides of ring 10 spanning the portion of the guideway receiving bearing parts 11 are secured elongated plates 18, and these plates journal the reduced ends 19 of a screw 8|! having the threads thereof oppositely arranged from the center thereof whereby the portion thereof which extends through one of the bearing parts 11 is oppositely arranged in comparison to the portion thereof which extends through the other bearing portion 11. By this arrangement, rotation of the screw 88 in one direction separates the bearings in each guideway, and reverse rotation shifts said bearings toward each other.

In the other part of the ring 1i) is mounted a third bearing 8| which is preferably positioned at or adjacent 120 degree relation tov the bearings 13. This third bearing 8| is preferably adjustab-le radially of the ring 10, for which purpose a substantially rectangular guideway 82 is provided in the ring 1i) to open to the inner periphery of the ring. In guideway 82 is mounted a block 83 adapted for adjustment radially of the ring by means of a radially positioned adjusting screw84 which has threaded connection with said block 83. The head 85 of screw 84 is preferably inset with relation to the teeth of gear ring 10, and suitable means such as a stop 86 threaded in the aperture receiving the screw head, is provided to lock the part in desired radial adjustment. The block 83 is provided with a configured guideway 81 extending parallel to the shaft axis in which the bearing 8|, which is of substantially the same two-part construction as bearing 13 above described, is adjustable. The adjustment of bearing 8| is effected through the double-threaded screw 88 whose ends are journaled in the plates 89 carried by the block 83 to span the ends of guideway 81.

The bearings f3 and 3| provide means for adjusting the cutter type of device to the work. Thus, when the gear ring 18 has been assembled in operative locked relation encircling the work, the bearings 13 are adjusted in proper spaced relation by screws 88 to permit the projecting portions 16 thereof to ride on the two portions Y 68 of the shaft at the opposite ends of the eccentric or defective shaft portion. The bearing 8| is similarly adjusted, and is also radially adjusted by screw 84 to effect a three point bearing engagement of the device with the shaft at portions 56, thus providing guides which are adjustable both longitudinally and radially with respect to the work to permit use of the ring 10 with shafts of a wide range of sizes.

v In spaced relation to guideway 82 and block 83, and preferablyin the same ring part, is provided another substantially rectangular guideway Si) receiving a block 9| adjustable radially in said guideway 98 by means of screw 82. Block 9| is provided with a guideway 93 extending parallel to the shaft axis and c'ongured to receivev a cutter 94. Cutter 94 comprises a body one-half the cutter length. Projection 98 has a threaded bore therethrough in which a screw 99 is mounted. The ends of screw 9S are journaled in plates |88 secured to the sides of block 9| to span the outer portion of guideway 93 in said block. One end `of screw 99 projects outwardly of plate |00 and mounts a toothed wheel or fr gear I 8|.

Frame may be provided with a suitable portion |82 at any convenient portion thereof projecting from one face thereof. A radially extending groove ||l3 is provided in the outer face of portion |62 for the reception of the enlarged head |04 of a finger |85 projecting radially inwardly from said frame in the plane of gear |0l. The head |84 is provided with an elongated slot H36 by means of which the same may be adjusted in groove |83 with respect to the' securing screw |01 extending into the frame and serving to lock the finger in desired adjustment. 'Ihe linger |05-is adapted to extend into the path of movement of the teeth of gear IUI.

In operation, the bearings having been adjusted and seated on portions 88 of the shaft, the cutter block is adjusted to position the cutter in proper relation to the shaft to effect the cut desired. Screw 99 is then rotated to position the cutter at one end of shaft portion v55 to be trued, as illustrated in Fig. 11.' Frame 20 is then assembled around ring 10, and finger |05 is adjusted for engagement with the teeth of gear IUI. The gear ring 'l0 is driven by the Worm gear 3| of the frame in the manner previously described, the said ring 'l0 rotating in true circular movement guided by bearings T3 and 8l, which, as heretofore described, also serve to prevent movement or play of the ring longitudinally on the shaft. This guiding of the ring 10 serves also to guide cutter 94 which is held in fixed adjustment to ring 7D. Therefore, the extent of the cut taken by the cutter at any particular portion of the shaft surface depends entirely upon the condition of the shaft at that point. In other Words, the cutter will take a comparatively heavy cut at the high spots on the shaft, and a comparatively shallow cut at the low spots. In cases of extreme shaft deformity, the cutter may ride out of contact with the shaft at certain of the low spots or pits.

As the gear ring l!) rotates, it carries with it gear IUI, and upon each rotation the outermost tooth of said gear strikes the end of finger 105, whereby said gear is rotated to a small extent to rotate screw 99 an equal amount and advance the cutter a slight extent upon each rotation of ring l0. By measuring the length of the shaft surface to be trued, the time required for passing the cutter over the shaft portion in question can be determined, and the operator can thus control the cutting operation accurately.

While the invention has been here illustrated and described as a power driven unit, it will be obvious that the frame 2 and associated driving parts are not essential. Thus, by forming either of the rings 40 or '10 of polygonal outline to facilitate gripping thereof by a Wrench or other tool, the shaft may be trued by hand. In this connection, it will be seen that the provision of the guides which ride on true portions of the shaft compensates for the tendency to apply all operating stress in one direction and prevents such action from interfering with the accurate result of operation of the device.

I claim:

l. Shaft truing means comprising a frame, an annular member rotatable in said frame, shaping means carried by and projecting from the inner periphery of said member, and guide means at the inner periphery of said member and riding on the portion of the shaft outwardly of the portion to be trued, said guide means having a positive constant relation to said shaping means to fully ycontrol the action of the shaping means.

2. Means for truing the defective portion of a shaft intermediate true portions thereof comprising a frame, an annular member carried by said frame, a truing member carried by said annular member, and means on said annular member engaging said true shaft portions for guiding said truing member circularly with respect to the axis of the shaft, said guide means having a constant predetermined position with relation to said truing member.

3. Means for truing a defective portion of a shaft comprising a member having an opening receiving a shaft, a rubber ring bonded to said member in said opening, a plurality of segmental plates bonded to said ring at the inner periphery thereof, abrasive material carried by the inner faces of said plates, and guide means associated with said plates and bearing on said shaft in spaced relation to said defective portion.

4. Shaft truing means comprising a member encircling the shaft and including an annular portion of resilient material, a plurality of seg ments facing the inner periphery of said member, said resilient material having parallel passages therein, said segments being spaced adjacent said passages, a flexible strip of abrasive lining said facing and having portions projecting into said passages, and retaining members engaging said projecting portions in said passages.

5. Means for truing a defective portion af a shaft comprising a member having a circular opening lined With resilient material, a ring of metal segments facing the inner periphery of said resilient material, and an abrasive ring carried by said segments intermediate the sides of said segments, the sides of said segments projecting beyond said defective portion for engagement with said shaft to control the action of said abrasive.

6. Shaft truing means comprising a two-part frame having a circular opening and a chamber communicating With said opening, means for securing said frame parts together, drive means in said chamber, a two-part annulus rotatable in said opening and energized by said drive means, shaping means carried by the annulus Within the inner periphery thereof, and means positioned in constant predetermined relation to said shaping means carried by said annulus and engaging the shaft in laterally spaced relation to the shaping means to guide the action of the shaping means.

JAMES P. FERGUSON. 

